In recent years, the sophistication of portable device functions, coupled with the increase of portable devices equipped with a location information processing function and compatible with services provided over a network, is making it difficult to achieve distinction from competitors by equipping or not equipping the portable device with a function.
Therefore, in order to develop a portable device that appeals to users, it has become important to put energy to more surficial aspects of a product such as the casing, screen design, and graphical user interface (GUI). Updating and accommodating the product to new services over a network after the product is shipped is also indispensable in order to motivate users to own and use the product for a long time. In addition, terminal price competition is accelerating, pushing the prices of portable devices further down.
Under these circumstances, in the field of location information device that have a car navigation function or the like, the following efforts for providing a device that appeals to users while keeping the cost low are attracting attention:
(1) Facilitating the introduction of new services: Enabling a navigation system to communicate, adding a service in cooperation with a navigation service center which provides map information and the like, and equipping the terminal with a widget which provides information on the display screen.
(2) Facilitating the acquirement of a screen and contents, and reducing the development span: Promptly incorporating requests of the designer. Utilizing contents that are provided by a user or a third party. Passing around contents among a plurality of users.
The above-mentioned contents used on a location information device can be applications such as a widget displayed on a display of the location information device.
A “widget” refers to a single-function application that is written in XML and a script language and that is displayed all the time in a part of the screen of the display.
In many conventional location information devices, however, all the equipped functions have already been configured in advance in order to accomplish smooth operation while ensuring the user's safety with limited hardware resources (CPU performance, memory capacity, and the like), and the operation of each function, too, is strictly managed at the manufacture stage to give the terminal a structure that reduces operation failures or the like as much as possible. Consequently, adding functions after a location information device is shipped, which is necessary to accomplish the above items (1) and (2), is difficult to carry out while guaranteeing safety and smooth operation. With a location information device that has few hardware resources to spare, in particular, it is a possibility that an added function may interfere with an existing function in unexpected situations, making the terminal operation unstable.
Screen display control method that address to these problems have been proposed. For example, Patent Literature 1 proposes a method in which screen data to be output to a display is divided into drawing elements and methods of animating the drawing elements in order to manage the two separately and, when one drawing element is displayed, an animation is output in accordance with an animation method that is associated with the element if certain conditions are satisfied.